\begin{tabular}{@{}lrr@{ = }l@{}}
\toprule
\thead{Ingredient} & \thead{Baker's math} & \multicolumn{2}{c}{\thead{Calculated value}} \\ \midrule
Flour               & 100\%   & $1400 \times 1$ & 1400g         \\ 
Water               & 60\%    & $1400 \times 0.6$ & 840g        \\ 
Sourdough starter   & 10\%    & $1400 \times 0.1$ & 140g        \\ 
Salt                & 2\%     & $1400 \times 0.02$ & 28g        \\ \bottomrule
\end{tabular}